1. Field of the Invention
The present invention relates to a semiconductor device having a component such as an interconnection pattern mounted on a substrate and a method of manufacturing the same and, more particularly, to a semiconductor device having a lower surface on which pieces of product information including the model name and lot number of the device itself are printed, and a method of manufacturing the same.
2. Description of the Related Art
In packaging a semiconductor device made of Si or GaAs, flip chip connection by direct face down is used to make the device compact and lightweight. The packaged semiconductor device always undergoes a test step. For this purpose, pieces of product information including the model name and lot number of the device itself, and an index mark, test mark, and the like are printed on the lower surface of the device by ink or laser marking, as described in, e.g., Jpn. Pat. Appln. KOKAI Publication Nos. 2000-114129, 2001-85285, 8-191038, and 4-106960.
On the other hand, since such a semiconductor device aims at decreasing the thickness, its lower surface is normally mirror-finished by a grinder. Since the lower surface is glossier than the product information and marks, the semiconductor device is not suitable for automatic testing by an optical test apparatus for the product information and marks. As a measure against this, an ink application portion with a lower light reflectance than that of the substrate is formed, as described in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2003-318335. Alternatively, the lower surface, which is mirror-finished and has product information and marks, is wholly subjected to surface roughening on purpose. With this process, contrast is suppressed in accordance with the product information and marks. Accordingly, the product information of the semiconductor device can be read or the mark position can be recognized by using an optical test apparatus.
Examples of surface roughening are sand blasting, lapping using abrasive grain, and etching using hydrofluoric-acid-based mixed acid. With such surface roughening, the lower surface of the semiconductor device is physically or chemically nonuniformly ground. This suppresses the gloss on the entire lower surface and allows automatic testing by an optical test apparatus.
Conventionally, the lower surface of a semiconductor device is temporarily mirror-finished. After that, a product information mark and index and test marks are formed on it. Then, the lower surface is roughened.
However, when surface roughening is performed, marks printed by ink become partially invisible. For marks formed by laser marking, their three-dimensional patterns are partially shaved. For this reason, the mark recognition accuracy in automatic testing by an optical test apparatus may be low.
To avoid this, the marks may be formed again after surface roughening. However, when marks are printed by ink on the roughened surface, the ink blots, and the marks blur. It therefore provides no practical solution. Even laser marking can form no stable pattern on the roughened surface because of its three-dimensional pattern. It provides no practical solution, either. When sand blasting or etching using mixed acid is applied, only a necessary portion can be roughened. However, these methods are disadvantageous because they require many additional steps such as photolithography, cleaning, and rinsing.
As shown in FIGS. 1 to 5, a semiconductor device 18 includes a silicon substrate 60, sealing resin 28, and a plurality of external connection terminals 36. When the semiconductor device is to be split along split lines 25 and separated into semiconductor devices 16, a dicing tape 20 bonded to a dicing jig 62 in advance is bonded to the lower surface, as shown in FIG. 1. The general dicing tape 20 is formed from an adhesive and a base film member. As the adhesive, acrylic resin is used. As the base film material, vinyl chloride resin is used.
To separate the semiconductor devices 16 from the semiconductor device 18, the semiconductor device 18 is cut by a dedicated dicing blade 17 along the split lines 25, as shown in FIG. 2. Then, the semiconductor devices are placed on an expander constituted by a stage 66 incorporating a heater 64, and a ring 68, as shown in FIG. 3. The dicing tape 20 is heated by the heater 64. After that, the stage 66 and ring 68 are pushed upward in FIG. 3 by a known elevator mechanism while the dicing jig 62 is fixed not to move. As shown in FIG. 3, the distance between the semiconductor devices 16 adjacent to each other increases as the dicing tape 20 stretches so that the semiconductor devices 16 are separated from each other. As shown in FIG. 4, the dicing tape 20 is cut between the ring 68 and the dicing jig 62 and detached from the stage 66. The dicing tape 20 is irradiated with UV rays 70 from its lower surface side. The adhesive force of the acrylic resin used as the adhesive of the dicing tape 20 is weakened by this irradiation of UV rays. After the adhesive force is weakened, the dicing tape 20 is removed from the lower surface of each semiconductor device 16, as shown in FIG. 5.
In this case, if the three-dimensional pattern formed for a mark is sufficiently small, the dicing tape 20 can easily be removed from the lower surface. When the three-dimensional pattern is large to some extent, the dicing tape 20 may weld along the three-dimensional pattern and be difficult to remove.